The use of wave suppressors is generally well known. For example in U.S. Pat. No. 3,304,560 a turbulence reducing device is shown in which a plurality of lattice devices are strung the length of the swimming pool. Float means are attached to the ends of each of the devices to maintain buoyancy if the device is formed of a nonbuoyant material. This suppressor was one of the earliest attempts to suppress wave transmission between swimming lanes.
Numerous other devices have also been proposed to better suppress turbulence in competitive swimming pools, e.g., U.S. Pat. Nos. 3,540,063; 3,755,829; 3,786,521; 4,048,677 and 4,052,755. In general, these "racing lanes" consist of a plurality of elements strung on a cable that extends the length of the pool and define the boundaries of the swimming lanes. Each element is configured as a particular axially symmetric shape designed to suppress or inhibit the propagation of waves generated by a swimmer into the lane of another swimmer. Of these, U.S. Pat. No. 3,755,829 has found commercial success in the marketplace.
Another such device of particular interest is disclosed in U.S. Pat. No. 3,886,602. The device disclosed has a plurality of discs positioned perpendicular to the cable and is manufactured from a foamed plastic so that each element is capable of floating without separate flotation means. This device overcame many of the objections of the prior art devices which do little more than mark the lanes. However, because of its size and shape it permitted the majority of wave energy to pass from one pool lane to another. Additionally, it was difficult to handle and store and expensive to manufacture.
U.S. Pat. No. 4,894,873 discloses a wave suppression device comprised of a cylindrical core having a plurality of fins radially extending from its outer surface. The fins create enclosures which trap water motion, thus creating random turbulent motion which dissipates the viscous forces of water. This device includes a central channel for receiving a cable-like device for stringing a plurality of wave suppression devices together to form a lane demarcation. This device was designed to be sized to match and suppress the waves generated primarily by a swimmer, as well as by ships and the like. It was learned upon application of the device to large waves in harbor and marina areas, however, that the device had limitations. More specifically, it was difficult to maintain a desired buoyancy due to the force and energy of larger waves encountered in such an environment and also due to leaking of water into the interior of the device.
Accordingly, it is the object of the present invention to provide a device which has particular application in harbor and marina areas. More specifically, the buoyancy of the present device may be adjusted to interact in a desirable manner with the waves encountered in a particular harbor or marina environment.
In general, the present invention provides a wave suppression element which is comprised of a cylindrical hollow core having a plurality of fins radiating therefrom and which extend substantially the length of the core. Discs are located at and positioned circumferentially around each end of the core, which discs interconnect with and support the fins. The combination of fins and discs define wave entrapment cavities. Coextensively within the core is a channel for placing a cable or other securing means in which a plurality of elements may be strung.
In a preferred embodiment, the cylindrical core, fins and end disc, are formed from rotationally molded polyethylene, with each element being interconnected to the others and the invention being hollow throughout. A removable plug is located on the exterior of the core and between two (2) fins, which allows water or other material, e.g. sand, to be poured into the hollow interior of the device in order to obtain a desirable buoyancy. The plug is then sealed to make the device water tight and to retain the volume of water poured into the hollow interior of the device.
In a preferred embodiment, a polyethylene pipe is molded into the coextensive cable channel in the core. Further, it is also preferred that both ends of the core channel have threads designed to receive a bushing which, when screwed into the core threading, acts to secure the polyethylene pipe in the core area. In addition, the bushing can act to secure the wave suppression element to the cable or similar stringing means passing through the core channel.
When placed in a series along a cable or other stringing means, the wave suppression element can be prevented from moving along the stringing means through use of splices at various lengths. In addition, the element can be anchored at various points using chains, shackles and concrete blocks.
Other advantages of the invention will become apparent from a perusal of the following detailed description of a presently preferred embodiment of the invention.